Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
  • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
  • G03C5/29—Development processes or agents therefor
  • G03C5/30—Developers
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
  • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
  • G03C5/29—Development processes or agents therefor
  • G03C5/31—Regeneration; Replenishers

Definitions

• pepper spots often develop, as reported by Yule, in Journal of the Franklin Institute, March 1945, pages 221 to 230. It has now been found that such pepper spots often become prevalent when such developers are prepared from concentrated solutions which include an alcohol, such as ethyl alcohol, diethylene glycol or mcnomethyl ether of ethylene glycol; and the developing process and reenergizer of the present invention are not limited to such alcohol-containing developers, but extend the useful life of formaldehyde bisulfite developers in general.
• an alcohol such as ethyl alcohol, diethylene glycol or mcnomethyl ether of ethylene glycol
• replenishers for photographic developers generally comprise a substantial quantity of a developing agent, such as hydroquinone; enough suliite, such as sodium sulfite, to prevent aerial oxidation of the developing agent; and an alkaline material, such as sodium hydroxide or carbonate, sufii cient to restore the partially exhausted developer bath to approximately its original activity.
• a developing agent such as hydroquinone
• suliite such as sodium sulfite
• an alkaline material such as sodium hydroxide or carbonate
• an infectious developer bath consisting essentially of a water solution of hydroquinone as the sole developing agent, carbonyl-alkali metal bisulfite, preferably formaldehyde-alkali metal bisulfite, alkali metal hydroxide, carbonate or borate and a restrainer such as potassium bromide
• a restrainer such as potassium bromide
• the infectious de 'eloper bath after it has been partially exhausted and would normally be discarded, may be reenergized and restored to substantially its original activity by mixing with it a small amount of the reenergizer, and the capacity of the developer bath may be increased to as much as 3, 4 or more times its normal capacity.
• the present invention has for its object the provision of novel and improved method of reenergizing and greatly extending the useful life of an infectious developer bath.
• a further object is the provision of a novel and improved reenergizing solution for partially exhausted infectious developer baths.
• Another object is the provision of a novel and improved method of preventing undesired spots when using formaldehyde-bisulfite developers which include an alcohol in their composition.
• Still another object is the provision or" a novel and improved reenergizing solution by which an infectious developing bath may be maintained at good Working standards over a greatly extended film capacity, thereby resulting in greater economy and more uniform developed negatives.
• baths of litho developers may be reenergized after their normal useful life by adding to them small amounts of a concentrated aqueous solution of a sulfite ion and an alkali.
• a concentrated aqueous solution of a sulfite ion and an alkali comprises sulfite ions, hydroxyl ions and one or more alkali metal ions, such as sodium and potassium.
• alkali metal ions such as sodium and potassium.
• a mixture of different alkali metal ions are preferred so that the reenergizing solution may be more concentrated, although either sodium or potassium ions alone may be employed.
• the reenergizing solution consists of sodium or potassium sulfite or bisulfite and sodium or potassium hydroxide or carbonate, preferably sodium, potassium, sulfite and hydroxide ions.
• This may be provided by a concentrated water solution of sodium sulfite and potassium hydroxide, such solution being as concentrated as can be reliably stored and shipped without crystalliza tion.
• Typical of the formaldehydebisullite developers which may be used in the process of the present invention are those compounded within the ranges of the following general formula: i
• the quantity of the alkali used is chosen so that a pH range between 9.8 and 10.8 is obtained.
• Reenergizers for such litho developers consist essentially of a concentrated water solution of sodium and potassium llOIlS and of hydroxyl ions and sulfite ions, and are preferably composed of sodium or potassium hydroxide or carbonate and/ or borate and sodium or potassium suliite or bisulfite, the alkali metal ions preferably being mixed.
• a solution may consist of:
• Typical of the infectious developers which are usually reenergized by the method of the present invention are the following; with respect to each of which the preferred reenergizer solution and its manner of use is specified:
• Example 1 Solution A Formaldehyde potassium bisulfite monohydrate grams 110 Hydroquinone do 135 7 Potassium hydroxide 45% water solution ml 2.8 Diethylene glycol ml 118 Ethylene diarnine tetracetic acid grams 0.26 Water to make 1000 ml.
• equal parts A and B are mixed and diluted with 4 parts of water to make six liters of working developer for development of litho film.
• Potassium borate (anhydrous) "grams-.. 160 Potassium carbonate sesquihydrate do 204 Potassium bromide do 11.0
• solution A and one part of solution B are mixed and diluted with 3 to 5 volumes of water based on the total volume of A and B solutions to. make 7 the working solution for development of litho film.
• This developer bath may be reenergized several times v 4 by the addition to the bath of 5 to 40 cc. replenishing solution consisting of:
• one part of A is mixed with six parts of water and with one part of B to make a working developer.
• the reenergizer may comprise:
• one part of A and one part of B are added to two parts of water and mixed.
• Example 5 Another example of a litho developer and its reenergizer according to the present invention is as follows:
• solutions A and B are mixed, and may be reenergized by additions of the energizer solution C.
• Example 6 Still another infectious developer and its reenergizing solution have the following formulation:
• Equal parts of solutions A and B are mixed for use.
• the developer When somewhat exhausted, the developer may be reenergized by adding 10 to 50 ml. of the Solution C per liter of developer, and may be repeated several times.
• the renergizing solutions are preferably highly concentrated but may be diluted, so long as the working developer is not seriously diluted by their addition.
• a solution such as Solution C of Example 1 may be diluted with 5 parts of water and from 150 to 1200 ml. used for each six liters of partially used Working developer.
• such dilution impairs the working developer, and for that reason, the reenergizer should be as concentrated as is practically possible.
• a process for reenergizing and maintaining the activity of a hydroquinone containing carbonyl-bisulfite developer for lithographic film the hydroquinone being the sole developing agent, which comprises adding to the developer, after some film has been developed therein, an aqueous solution consisting essentially of from 0.5 to 10 grams of an alkali metal sulfite and from 0.1 to 3.2 grams of an alkali metal hydroxide per liter of developer, the said aqueous solution being substantially free of hydroquinone and other organic developing agents.
• a process for reenergizing and maintaining the activity of a hydroquinone containing carbonyl-bisulfite developer for lithographic film the hydroquinone being the sole developing agent, which comprises periodically adding to the developer, per liter of developer, from about 5 to 50 cc. of an aqueous solution consisting essentially of from 100 to 250 grams per liter of an alkali metal sulfite and from 20 to grams per liter of an alkali metal hydroxide, the said aqueous solution being substantially free of hydroquinone and other organic developing agents.
• a process for reenergizing and extending the activity of a used hydroquinone-containing formaldehyde-alkali metal-bisulfite developer for lithographic film the hydroquinone being the sole developing agent, which comprises periodically adding to the developer, per liter of developer, from about 5 to 50 cc. of aqueous solution consisting essentially of from to 250 grams per liter of an alkali metal sulfite and from 20 to 80 grams per liter of an alkali metal hydroxide, the said aqueous solution being substantially free of hydroquinone and other organic developing agents.
• a process as in claim 4 wherein the alcohol is selected from the group consisting of diethylene glycol and triethylene glycol.
• a re-energizing solution for periodic addition to a carbonyl-alkali metal-bisulfite developer having hydroquinone as its sole developing agent consisting essentially of an aqueous solution of sulfite and hydroxyl ions and associated alkali metal ions selected from the group of salts consisting of sodium and potassium sulfites in a quantity of from 100 to 250 grams per liter and sodium and potassium hydroxide of from 20 to 80 grams per liter.

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Citations (2)

• 0
  • BE BE631419D patent/BE631419A/xx unknown
  • NL NL292635D patent/NL292635A/xx unknown
• 1962
  • 1962-06-26 US US205215A patent/US3162534A/en not_active Expired - Lifetime
  • 1962-09-10 LU LU42330D patent/LU42330A1/xx unknown
  • 1962-09-10 CH CH1070962A patent/CH433008A/fr unknown
• 1963
  • 1963-03-04 GB GB8509/63A patent/GB1035034A/en not_active Expired

Patent Citations (2)

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